In a point-to-multipoint network, such as a passive optical network, data transmissions from downstream devices are typically coordinated by sending grant messages to give permission to the downstream devices to send data over a shared communication medium. Such messaging procedures, and other existing network management techniques, use bandwidth and processing resources. As the number of downstream devices sharing the communication medium increase, these messaging procedures become inefficient. Thus, there is a need for more sophisticated methods and systems for managing data transmissions.